Interior vibrator with rotating unbalance

ABSTRACT

An inner vibrator with an unbalance body of cylindrical shape adapted to roll on the inner mantle of the housing for the vibrator, for compacting concrete and similar material, in which said unbalance body has one end provided with a short pivot which engages a bore of an eccentric disc drivingly connected with the motor shaft, the diameter of said bore being greater than the diameter of said pivot to such an extent that the unbalancing force produced by the rolling movement of the cylindrical unbalance body will not be transferred to the eccentric disc.

United States Patent Inventor Philipp Uebel Munich, Germany App]. No. 887,119 Filed Dec. 22,1969 Patented Aug. 24, 1971 Assignee Wacker Werlre KG Munich, Germany Priority Dec. 21, 1968 Germany P 18 16 421.1

INTERIOR VIBRATOR WITH ROTATING UNBALANCE 4 Claims, 3 Drawing Figs.

U.S. Cl 259/1, 259/DlG. 41

Int. Cl B011 11/00 Field of Search 259/1 DIG.

41, DIG. 42, DIG. 43

[56] References Cited UNITED STATES PATENTS 3,152,790 10/1964 Meyer 259/1 3,152,791 10/1964 Svensson... 259/1 3,236,502 2/1966 Eisenbeis... 259/1 3,286,991 11/1966 Pellegatti... 259/1 Primary Examiner-Robert W. Jenkins Artomey- Walter Becker ABSTRACT: An inner vibrator with an unbalance body of cylindrical shape adapted to roll on the inner mantle of the housing for the vibrator, for compacting concrete and similar material, in which said unbalance body has one end provided with a short pivot which engages a bore of an eccentric disc drivingly connected with the motor shaft, the diameter of said bore being greater than the diameter of said pivot to such an extent that the unbalancing force produced by the rolling movement of the cylindrical unbalance body will not be transferred to the eccentric disc.

PATENIEU M2419?! v 3.601.368

INVENTOR. PHILIPF UEBEL INTERIOR VIBRATOR WITH ROTATING UNBALANCE The present invention relates to an interior vibrator with rotating unbalance and, more specifically, with an unbalance body of cylindrical shape which rolls on the inner mantle of the housing of the vibrator.

Vibrators have become known which are employed in particular for compacting concrete and in which that part which produces the unbalance is fixedly mounted on a rotating shaft. With this type of vibrators, the force upon the material to be compacted becomes effective toward the outside through bearing means. Such vibrators encounter a considerable wear in the bearing means due to the enormous load, and the power effect is considerably dampened by the bearing means.

Furthermore, vibrators with circulating unbalance have become known according to which the unbalances roll on the inner mantle of the vibrator and are guided over the entire length by guiding means which are fixedly connected to the shaft. To guide the unbalance over the entire shaft means, however, that the unbalance between the shaft and the inner side of the mantle can have only a relatively small mass. Moreover, the friction in view of the long guiding means for the unbalance is relatively high, which fact makes itself felt in a poor degree of deficiency of these last-mentioned vibrators.

Also, interior vibrators with rolling unbalance have become known which operate in conformity with the principle of the pendulum strike lever. With this type of vibrators, a strike lever is rotated by means of a flexible shaft while the lower thicker portion of said strike lever rolls along a path in the interior of the vibrator housing. The strike lever is journaled in the upper portion of the vibrator housing. This bearing is subjected to high stresses and thus likewise is subjected to very high wear.

There are also known interior vibrators in which a rolling unbalance body in the interior of the device is driven by devices equipped with joints. This design has the drawback that it requires a considerable space in view of the joints.

Vibrators driven by a crank pin have become known which roll in the interior of the device. The unbalance body is, through bearing means, journaled on the crankpin and is connected and guided by suitable means. The drawback of this arrangement is seen primarily in that the bearing elements wear quickly since when the outer diameter of the unbalance body is somewhat worn they have to absorb the centrifugal force. Inasmuch as the unbalance body rolls in the housing of the device in a direction opposite to the driving crankpin, the two velocities add up at the outer ring of the bearing element which results in an increased wear.

Finally, vibrators have become known in which the unbalance rolling in the housing is driven by means of an eccentric pin with soldered-on hard metal plates without the intermission of bearing elements. With this type of devices, experience has proved that the hard metal plates break out and furthermore the quality of soldering depends on the operator who has performed the soldering operation.

It is therefore an object of the present invention to provide an interior vibrator with rotating unbalance, which will overcome the above mentioned drawbacks.

It is another object of this invention to provide a vibrator as set forth in the preceding paragraph which will have a higher output with decreased wear while employing simplified means.

These and other objects and advantages of the invention will appear more clearly from the following specification, in connection with the accompanying drawing, in which:

FIG. I is a vertical section through an interior vibrator according to the present invention.

FIG. 2 illustrates in section a hollow unbalance body according to the invention filled with a metal heavier than the metal of which said hollow unbalance body is made.

H6. 3 is a section through a modified unbalance body according to the invention which differs from that of !FIG. 2 in that it is solid.

The inner vibrator according to the present invention is characterized primarily in that the cylindrical unbalance body has one end thereof provided with a short pivot which extends into the bore of an eccentric drivingly connected to the driving shaft, and is furthermore characterized in that said bore of the eccentric has such a diameter that the unbalancing force which is produced by the rolling of the cylindrical unbalance body will not act upon the eccentric.

According to a further feature of the present invention, wear-resistant bushings are provided in the bore of the eccentric and on the short pivot of the cylindrical unbalance body.

Moreover, if desired, in the unbalance body there may be provided a central bore for receiving heavy metallic bodies.

Referring now to the drawing in detail, the arrangement shown therein comprises an inner vibrator having a housing 1 into which extends a driving shaft 2, for instance of an electric motor, which is surrounded by the stator winding of said motor, only the lower stator packet 2a being shown. Shaft 2 is in customary manner provided with longitudinal grooves having copper strips inserted therein. Shaft 2 is provided with an extension 2b having press-fitted thereon the shank 3a of an eccentric 3 in such a way that a firm connection is established between shaft 2 and the eccentric 3. Shank 3a is partly journaled in antifriction bearing means 3b. Eccentric 3 has has eccentrically arranged therein a bore 4. A pivot 5 of a cylindrical unbalance body 6 extends into the said bore 4. The inside cylindrical bore 4 and the outer peripheral surface of the pivot 5 may be provided with a wear-resistant bushing 7 and 8 respectively. Such wear-resistant bushings may consist of hard metal or polytetrafluorethylene which may be intermixed with glass to increase the wear resistance. The cylindrical unbalance body 6 may be provided with a central bore 9 which may be filled with a metal heavier than the material of the unbalance body 6 which latter is preferably made of steel. As such filling metal which is, e.g. firmly pressed into bore 9 may be used, for example, lead or hard metal.

In some instances, it may also be advantageous instead of using a hollow metal filled unbalance body 6 (FIG. 2) to employ a solid unbalance body 60 as shown in FIG. 3.

As will be seen from FIG. 1, closure cap 10 is provided with a bore 10a which in addition to reducing the overall weight of the vibrator serves as reservoir for the lubricant, e.g. oil. Finally, FIG. 1 also shows the center line M1 of the vibrator and the center line M2 of the unbalance body 6. The distance r between said center lines M1 and M2 is the radius of the center of gravity.

The operation of the device described above is as follows: When shaft 2 is rotated by the motor (of which only stator packet 2a is shown), the rotation of shaft 2 is conveyed through shank 3a to the eccentric 3 so that the latter will rotate. The rotation of eccentric 3 is conveyed through bore 4 with bushing 7 to bushing 8 and pin 5 of the eccentric 6 which latter then exerts an unbalancing movement.

As will be evident from the above, an important advantage of the vibrator according to the invention is seen in its simplified construction and manufacture, especially as far as the cylindrical unbalance body 6 and the eccentric 3 are concerned. Furthermore, over heretofore known vibrators with unrolling unbalance, according to which the pin of the eccentric extends into a bore of the unbalance body, the vibrator according to the invention has the advantage that with the same outer volume of the unbalance, the mass is greater and consequently also the centrifugal force is higher.

It is, of course, to be understood that the present invention is, by no means, limited to the showing in the drawing, but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. An interior vibrator, especially for compacting concrete and similar material, which includes: housing means having an inner wall surface, an unbalance body rotatably arranged within said housing means and having an outer cylindrical surface adapted to roll on said inner wall surface, eccentric means rotatably journaled in said housing means and provided said bore.

3. A vibrator according to claim 1, which includes a bushing v of wear-resistant material forming the peripheral surface of of wear-resistant material arranged on the inside surface of l0 said pivot.

4. A vibrator according to claim 1, in which said unbalance body is provided with a substantially central bore, and which comprises relatively heavy bodies movably arranged in said central bore. 

1. An interior vibrator, especially for compacting concrete and similar material, which includes: housing means having an inner wall surface, an unbalance body rotatably arranged within said housing means and having an outer cylindrical surface adapted to roll on said inner wall surface, eccentric means rotatably journaled in said housing means and provided with a bore open toward said unbalance body, said unbalance body having a pivot extending into said bore, and motor shaft means connected to said eccentric means for rotating the same, the diameter of said bore being greater than the diameter of said pivot to such an extent as to prevent the transfer of unbalance forces from said unbalance body to said eccentric means.
 2. A vibrator according to claim 1, which includes a bushing of wear-resistant material arranged on the inside surface of said bore.
 3. A vibrator according to claim 1, which includes a bushing of wear-resistant material forming the peripheral surface of said pivot.
 4. A vibrator according to claim 1, in which said unbalance body is provided with a substantially central bore, and which comprises relatively heavy bodies movably arranged in said central bore. 